William smith paca



(No Model.

W. S. PACA.

ELECTRIC ANNUNGIATOR CALL.

No. 426,807. Patented Apr. 22, 1890.

-IN\/ENTUFL- UNTTE STATES PATENT OFFICE.

WILLIAM SMITH PACA, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE EASTERN ELECTRIC COMPANY, OF SAME PLACE.

ELECTRIC ANNUNClATOR-CALL.

SPECIFICATION forming part of Letters Patent No. 426,307, dated April 22, 1890.

Application filed November 2'7, 1889- Serial No. 331,801. (No model.)

T0 or whom, it may concern:

Be it known that I, WILLIAM SMITH PACA, of the city of Baltimore, and State of Maryland, have invented certain Improvements in Electric Calls, of which the following is a specification.

-In buildings where a system of speakingtubes is employed and arranged so that communication may be had from one room with all the others the mouth-pieces are each provided with a whistle, and in calling one room the whistles of all the others are sounded. To prevent confusion, a peculiar call is sometimes adopted for each room or floor, but notwithstanding this expedient all the whistles are sounded, and no privacy can be maintained in transmitting messages, as each room is notified by sound that a communication is about to be made and it is only necessary for -any one to place his ear to any mouth-piece to ascertain its character.

The principal object of my invention is to arrange a system of calls so that an alarm is sounded only in the apartment with which communication is sought; and the invention consists in placing in each room or apartment a magneto-bell and a switch-board in an open circuit, having points connected by wires to the call-boxes in all the other rooms, and a switch-strap which may be made to form a connection between the magneto-bell in any other room and the point 011 the switch-board which represents it, as will hereinafter fully appear.

In the further description of the said invention which follows reference is made to the accompanying drawings, forming a part hereof, and in which Figure 1 is a sectional elevation of a build ing with four rooms or floors to which my invention is applied. Fig. 2 is a rear view of one of the call-boxes with the back thereof removed and shown on an enlarged scale.

In the said drawings, A, B, C, and D represent the rooms or floors oi the building, and E, F, G, and H call-boxes in the respective rooms, each containing a magneto-bell.

I, .I, K, and L are switch-boards in the various rooms. A wire 11 leads from one connection of each magneto-bell to the switch strap M of its switchboard, and another wire 6 leads from the other connection of the bell or ringer to a point representing the room or floor on all the switch-boards in the building or system except its own. A third wire 0 con- 5 5 stitut-es the return-circuit wire to which all' the calls are connected.

Room 1 has on its switch-board points marked 2, 3, and 4. Room 2 has its switchboard provided with the points 1, 3, and 4, and so on, each switch-board having a point numbered to represent each room or floor except the one in which it is situated.

Referring to Fig. 2, which, as before stated, is a rear view of one of the boxes with the back thereof removed, N is the generator, which is of the usual type, and 0 represents the ringing coils and magnets. The three posts to which the wires a, b, and c are attached are respectively denoted by (Z, c, and f. One connection of the generator runs to the post (Z and the other to the post f. The post (2 unites with one connection of the ringing coils, and the other connection taps the generatonwire at g.

From the foregoing it will be understood that all the call-boxes are in a nor1nally-open circuit, and that the closing of the circuit for any room affects only the call-box in that room which is sounded.

As only one call is sounded by moving a switch-strap to contact with a point on the switch-board, lower-resistance coils may be employed in the call-boxes than if several were rung, and the construction of the callboxes is thereby cheapened.

R is a speaking-tube having the branches h,'z', j, and 7s and mouth-pieces Z, on, n, and 0 opening into the various rooms.

The operation of the invention is as follows: Supposing a person in room 1 wishes to communicate with another in room 4, he turns the switch-strap so that its end comes directly over the point 4, and then presses it in to close the circuit in which the ringing mechanism in room 4: only is included. He then turns the handle 19, which causes the magnetobell in room A to sound. Upon hearing the call the person in room 4 applies his ear to the mouth-piece of the speaking-tube and re- I00 ceives the communication.

The operation of calling from room 4; to

room 1, or from any room to another, is the same as that described, the snmmoner in all cases connecting his switch-strap with a point bearing a number corresponding with the room with which he desires to communicate.

While I have illustrated my invention by introducing a speaking-tube as the means of communication between the Various rooms, I do not limit myself to its use, as a telephone or telegraph instrument could be employed instead; or the system of calls, as described, could be used in connection with a dumbwaiter having openings at the several floors or rooms.

I claim as my invention 

